SSL II USER'S GUIDE - Lahey Computer Systems

CHAPTER 1
SSL II OUTLINE
1.1 BACKGROUND OF DEVELOPMENT
Many years have passed since SSL (Scientific Subroutine
Library) was first developed. Due to advancements in
numerical calculation techniques and to increased power
of computers, SSL has been updated and new functions
have been added on many occasions. However, users
have further requested the followings:
• Better balance of the functions and uses of individual
subroutines
• That addition of new functions not adversely affect the
organization of the system
• Better documentation of various functions and their
uses
SSLII was developed with these requirements in mind.
1.2 DEVELOPMENT OBJECTIVES
Systematizing
It is important for a library to enable the user to quickly
identify subroutines which will suit his purposes.
SSLII is organized with emphasis on the following
points:
• We classify numerical computations as follows:
A Linear algebra
B Eigenvalues and eigenvectors
C Nonlinear equations
D Extrema
E Interpolations and approximations
F Transforms
G Numerical differentiation and quadrature
H Differential equations
I Special functions
J Pseudo random numbers
These categories are further subdivided for each branch.
The library is made in a hierarchy organization. The
organization allows easier identifying the locations of
individual subroutines.
• Some branches have subdivided functions. We present
not only general purpose-oriented subroutines but also
those which perform as components of the former, so
that the user can use the components when he wishes to
analize the sequence of the computational procedures.
Performance improvement
Through algorithmic and programming revisions,
improvements have been made both in accuracy and
speed.
• The algorithmic methods which are stable and precise
are newly adopted. Some of the standard methods used
in the past are neglected.
• In programming, importance is attached to reducing
execution time. Thus, the subroutines, are written in
FORTRAN to enjoy the optimization of the compiler.
SSLII improves the locality of the virtual storage
system program, but does not decrease the efficiency of
a computer without virtual storage.
Improvement of reliability
In most cases, single and double precision routines are
generated from the same source program.
Maintenance of compatibility
Nowadays, developed softwares are easily transferred
between different type systems. The SSL II subroutines
are structured to maintain compatibility. A few auxiliary
subroutines which are dependent of the system are
created.
1.3 FEATURES
• SSL II is a collection of subroutines written in
FORTRAN and desired subroutines are called in user
programs using the CALL statement.
• All subroutines are written without input statements,
user data is assumed to be in main storage.
• Data size is defined with subroutine parameters. No
restrictions are applied to data size within subroutines.
• To save storage space for linear and eigenvalue-
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